Filter for well screens



April 23, 1929.

w. H. QATER FILTER FOR WELL SCREENS Filed April 27. 1925 11u, QQA? Patented Apr. Z3, 1929.

UNITED STATES WILLIAM II. CATER, F CHICAGO,l ILLINOIS.

FILTER FOR WELL SCREENS.

Application mea Aprii 27, 1925. serial No, 26,172.

In wells having reticulated or apertured Acasings or screens, it is frequently desired or required to provide them with external, enclosing filters to assure the purity of the water or other liquid supply which finds its way through the casing int-o its interior.

I have discovered that carborundum or its equivalent is a particularly appropriate, effective and efficient means for accomplishing this function and the present invention comprises valso the employment of such a filter to assist by its weight in causing the descent of the foraminous casing during the sinking of the latter in the ground.

Accordingly, in the preferred embodiment of the invention, the shoe or foot at the bottom of the casing, which cuts its way through the earth, is so formed that the carborundum filter, preferably made in arcuate sections designed to rest on one another and/ form a series of superposed rings or cylinders, will impose its weight thereon to help force the shoe and its associated l casing downwardly.

As the casing or screen descends new sections or layers of the encasing filter are applied to the lower layers thereof and thus the filter as a whole` is built up or formed progressively during the well sinking operation." Y.

To permit those trained in this art to fully understand thisv invention and its Various advantages, I Ahave illustrated the same in the accompanying drawing which forms a part of this specification and throughout the views of whichY like 4reference characters have been employed to designate the same parts.

In this drawing:

Figure 1 is a fragmentary yertical sectional view of a well undergoing the sinking operation or it may be considered 'an illustration of the lower portion only of a completed well;

Figure 2 is a plan view of one of the filter rings composed of interfitted arcuate sections, the endsof which are locked together; and

Figure 3 is a similar view of a modified form of filter element.

By reference to this drawing, it will be seen that the usual or customary apertured or perforated Icylindrical well casing or screen 11 hasa yShar -edged round foot 12 somewhat larger in iameter than the casing and which cuts or forces its way downsomewhat wardly through the earth during the well smkmg or driving operation, it being understood that the casing or screen is made of sect-ions or arts which are coupled together lengthwise 1n the usual way as the Well increases in depth, new sections being added at the top as is customary in operations of this kind.

The dirt or ground inside of the casing is removed during the driving operation by vmeans of a pump, not shown, in accordance with the conventional practice and in this way the casing gradually sinks down into 'f the ground, its contents being removed as it proceeds.

It is necessary-to weight the casing to cause its descent and accordingly the foot or shoe is supplied with an outstanding shoulder 13 on which the sectional carborundum filter 14 rests.

Each of the superposed layers or rings of the filter is preferably made of a plurality of arcuate or curved parts or sections 15 unitedl-y or conjointly forming a complete ring as is fully illustrated.

In order that the ends of such filter sections may be maintained in proper register and correct alignment, one end' of eachsection is provided with a groove or recess 16 adapted to receive a correspondingly-shaped tongue or lug 17 on the end of the adjacent or adjoining section, all as is clearly shown in Figure 2.

The lower layer or ring section of the filter rests or bears directly on lthe casing foot as is clearly depicted, and as the well sinking operation roceeds, other filter sections or layers or rlngs are applied around the casing on top of. those already fitted thereto, whereby their combined weight is employed to assist in driving or forcing the shoe and associated perforated casing downwardly into the earth.

When the casing reaches its proper depth, it will have been permanently encased or enclosed in a sectional or divided carborundum filter which seems to possess especially good filtering characteristics in relations of this character.

That is to say, carborundum performs the filtering operation efiiciently and without becoming unduly clogged by particles of the surrounding earth becoming embedded therein.

It is not alwa s necessaryto form the ends of the curved Iter sections with interlocking or intermatching features and such a filter 18 with plain ends is illustrated in plan in Figure 3. s

The invention is not necessarily limited and restricted to4 the precise and exact details of structure shown and described and thesemay be modified within comparatively wide limits Without departure from the heart and essence of the invention and without the sacrifice of any of its material benefits and advantages, the invention residing not only in the finished well but also in the method employed of sinking or driving the same wherein the weight of the filter is used to force the foot into the ground.

I claim:

l. The method of sinking a perforated single-wall sheet-metal well-casing having a lower foot of larger external diameter than that of the main body of the casing, consisting in forcing said casing downwardly into the earth progressively and assisting such descent by imposing on the exposed portion of such foot the gradually increasing weight of a filter enclosing the casing whose height is progressively increased by the addition thereto of successive superposed sections, each comprising a plurality of arcuate contacting filter elements unitedly forming such section.

2. The method of sinking a perforated single-wall sheet-metal well-casing having a lower foot of larger external diameter than that of the main-body of the casing, consisting in gradually forcing said casing downwardly into the earth and assisting such descent by imposing on the exposed portion of such foot the progressively increasing weight of a gradually elongating filter enclosing the casing, whose height and weightdescribed, the combination of a perforated single-wall sheet-metal well-casing having a foot of larger external diameter than that of the main body of the casing, and a carborundum filter enclosing this casing and resting on the outer exposed portion of said foot and composed solely of a plurality of superposed annular carborundum filter sections.

4f. In a well construction 'of the character described, the combination of a perforated single-wall sheet-metal Wall-casing having a foot of larger external diameter than that of the main body of the casing, and a filter enclosing this casing and resting on the outer exposed portion of said foot, said lter com-l prising superposed sections each of which is composed solely of several contacting filter elements conjointly forming the section.

5. In a well construction of the character described, the comA ination.of a perforated single-wall sheet-'metal Well-casing having a foot of larger external diameter than that of the main body of the casing, and a carbof rundum filter enclosing such casing and resting on the exposed portion of said foot, said filter comprismg superposed sections each of which is composed solely of several arcuate lcarborundum filter parts conjointly forming the section.

In Witness whereof I have hereunto set 

